title: Characterization and developmental expression patterns of testicular androgen-binding protein in the Djungarian hamster (Phodopus sungorus).
abstract: Studies were conducted to characterize Djungarian hamster androgen-binding protein and examine its expression during development. The cDNA encoding the full length testicular androgen-binding protein was cloned and, except for two suspected polymorphisms, shared a common primary sequence with hepatic sex hormone-binding globulin. A single androgen-binding protein/sex hormone-binding globulin gene was identified and a 1.7 kb mRNA encoding androgen-binding protein/sex hormone-binding globulin was present in both the testis and liver. Testicular homogenates contained specific 5 alpha-dihydrotestosterone-binding activity that was identified as androgen-binding protein. In the prepubertal testis, immunoreactive androgen-binding protein/sex hormone-binding globulin subunits ranged from 46 kDa to 60 kDa, with the majority of isoforms > 50 kDa. These subunits were distinct from the major 55 kDa and 51 kDa isoforms of sex hormone-binding globulin present in the serum of prepubertal hamsters. Deglycosylation studies demonstrated that size heterogeneities were the result of developmentally specific glycosylation patterns. Expression of androgen-binding protein by the testis was upregulated during puberty and coincided with a decline in serum sex hormone-binding globulin activity. The tissue- and age-dependent expression of specific androgen-binding protein and sex hormone-binding globulin variants suggests that these proteins play different roles in steroid-mediated sexual development.
authors.affiliation: Department of Anatomy and Cellular Biology, Tufts University School of Medicine, Boston, MA 02111, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Cates
authors.forename: D A
authors.initials: DA
authors.lastname: Damassa
mesh_terms: D000595:Amino Acid Sequence; D000727:Androgen-Binding Protein / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D015153:Blotting, Western; D006224:Cricetinae; D018076:DNA, Complementary / Q000032:analysis; D013196:Dihydrotestosterone / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006031:Glycosylation; D006801:Humans; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D017111:Phodopus / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017386:Sequence Homology, Amino Acid; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D012741:Sexual Maturation / Q000502:physiology*; D013737:Testis / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000727:Androgen-Binding Protein; D018076:DNA, Complementary; D012333:RNA, Messenger; D012738:Sex Hormone-Binding Globulin; D013196:Dihydrotestosterone